Shell fuze



Jan. 10, 1961 H. JUNGHANS El'AL 2,967,483

SHELL FUZE Filed NOV. 19, 1956 4 Sheets-Sheet 2 Fig.3

IN VEN TORS HELNUT JUNCrHANS 61 PAUL KMSER \VATSON, COLE, GRlNDLE \\\IATSON Jan. 10, 1961 H. JUNGHANS ETAL 2,957,483

SHELL FUZE Filed Nov. 19, 1956 4 Sheets-Sheet 5 Fig.5

INVENTORS \VATSON COLE, GFUND LE 3, \VATSON Jan. 10, 1961 H. JUNGHANS ETAL SHELL FUZE Filed Nov. 19, 1956 4 Sheets-Sheet 4 Fig. 6

Fig. ,7

JNVENTORS HELMUT JUNGHANSX PAUL KAISER BY I \vmsou, coLE, GRWDLE zuvATsoN United States Patent "ice when; ELLF ZH s m t u h nstck o r hr ls a; d

The present invention relates to an improvement of the shell fuze and'has for its object to improve itstim: ingsafety system inthat it indicates means by which the control of the timing safety element no longer takes place. gradually .but precipitately. The advantageof this measureiis that the timing safety device remains fully operative until the expiration of the predetermined safety period and is not, as hitherto, gradually withdrawn because. the effective control surfaces between the coope r ating elements gradually become smaller.

The improved arrangement according to the invention is characterized by the following featu'resz'Fo'r controlling the percussionpin safety locking device which re mains unchanged, an intermediate "lever constructed as a centrifugal lever is now provided which in turn when.

arrest and duringthe predetermined safety period is locked by an element operatively coupled for. movement.

with thefuze clockwork. r This arrangement pre'sentsthe advantage thatthe inter;

mediatelever'does not moveflduring". the entire Tsafety. period and therefore engages withits .e'ntire .bearing's'ur=. face under the collar of, the percussion pin right upto.

the end of, the safety period of the devicellocking, the

and even if this offers considerable resistance, there is,no danger of the locking parts being destroyed, for exam- P shears; ft. n ithadetsna pnbeia P erced;

e erred o m f con tru ccordinstq hi v om the em nt s rt en if a 2- W1 during he s f ty P i d s s ract atq th di h ng e the n o o e sea ement.

ou tedpn. P r s i P and. s P ov d d. t 1

bearing surface of a length corresponding to a predeterw mined. safety period and at the end :ofwhich. the centrifu; gal lever can drop olf; A centrifugalweight is. prefera: bly arranged onsth e outer extremity o-fthe toothed rack for; the purpose of assisting the ruhningdown'movement.

of theclockwork in the. initial stages;

The invention also includes" suitable safety means. for. the primer which incorporate'it the timing saf ety system of the percussion pin.

Other features and advantages of the. invention will become apparentl from the following description atone" form of, construction, from the drawings and from the" claims. In the form of, construction, illustrated by'way,

of example in the" accompanying drawings," theparts invention are omitted, and,

Fig.1 is fa longitudinal scction taken on line Il H which are. not necessary hfo rfthe' understanding of the att st after the removal of the mechanism plates locatedabove of Fig 2 in the, direction of the .arrows fshowing' .thej functional parts of the timing ,safe'tydevicle, inlpojsitionj Fig. 2 is a top plan view partly in sectiQnpf-Eig l- Patented Jan. 19, 196i the control elements of, the timing safety device;

Figs. 3 and 4 are similar views to those shown in Figs. 1 and" 2 with the timing elements of the safety device in the p'osition they assume at the end of the safety period;

Fig. 5 is a longitudinal section through the fuze with thefu'ze head and other structural elements removed, and shows the arrangement of a safety device for the detonator;

Fig. 6 shows, also in longitudinal section, a modified form of construction of the safety device for the detonator," the device being in safety position, and

Fig 7 shows the arrangement according to Fig. 6, viewed from above, the parts also being in safety position.

5 '10 designates the fuze cap, 11 the base, hereinafter referred to as the fuze screw; both parts are suitably recessed for accommodating the fu ze'clockwork-mechanism which is designated as a whole by the reference 12. The 'fuze clockwork mechanism is built up in the usual manner of separate mechanism plates between which the movable parts are mounted in suitable recesses. Arranged in the mean axis of the fine is the percussion pin 13, the'pointed end 13a of which has to pierce the primer'14 for 'the purpose of striking the detonator 15. The percussion pin 13 extends throughthe entire fuze clockwork mechanism 12 and the lower end of its cylindr ical stem serves as arbor for the movement regulator 19. This regulator has pallets 1911 which engage the teethof'the regulator wheel 20 and the pinion 21 coordinated to the wheel 20 meshes with the train wheel 22 which in turn is mounted for free rotation on the stem of the percussion pin 13 by means of its pinion23 drilled in longitudinal direction. The extension of the gear train from 'tlie pinion 23 to the centrifugal weight driven by the clockwork mechanism is- -not shown on the drawing because it is superfluous for understanding that which is'hereinafter described.

For locking the percussionpin 13 for a predetermined period'of. time (so-called block safety device), the percussion pin 13 is provided withacollar 13b under whichthe percussion .pin safety latch 39 engages by means of.

its arm 39a directed radially inwards. The latch 39 is mounted 'to swing onthe pin 28. The outwardly.directed end 390. of the latch is visible in a peripheral aperture..42a in .themechanism plate .42 for the purpose of control;

Anar'm. 39b .is. provided on. the underside of the latch 39 ;'a'nd extends through apertures .in the intermediate.

mechanism plates to a control pin38 :which is fitted on the upper side of a two-armed lever 100. The lever is .mounted onv thelmechanism platel32 to pivot about apin 38 and has two arms 100a, and 10%. The arm 1110;: on which thelpin 38-is arranged is heavier than the; arm 109b v andlocated in such a manner in relation 3 8a t the "termination of the time lock. The point of the arm 10Gb bears laterally against an abutment surface 102;: of a' centrifugal weight 102- which is fixed on a toothed rack'104 by means of rivets 103. The'rack 104 meshes with the teeth of the pinion 23 and is guided by suitable slide tracks32a and 35a worked in the mechanism. plates 32 and .35. The abutment or supporting surface 102a is, of a. length corresponding to the predetermined. time .safetyhpath and the lever. point 10% can drop off. the. end, of this-surface alt-102a causing the levertltlll towturn. As already. mentioned, this. turning movementtakes place in .counterclockwise direction under the action of the torque acting on the lever 100 itself (its arm 100a being heavier than the arm 10%) and in addition under the action of centrifugal torque acting on the latch 39 in the same direction.

The slide paths 32a and 35a for the rack 102, 104 are open towards the periphery of the fuze clockwork mechanism so that the person checking the setting can see at a glance on the completely assembled fuze clockwork mechanism whether in the fitting operation, the rack has been brought into its initial position as instructed and whether the latch is also in its safety position. The course of movements is hereinafter described.

The arrangements hereinafter described serve for further improving the safety of'the fuze according to the invention on the detonator safety device (Fig.

The mechanism plates 105, 106, 107 are mounted in a recess 11a in the underside of the fuze screw 11 and secured in position by means of a screw nut 109 screwed into the bore thread 11b and holding the detonator housing 108. The detonator safety slide valve 110 is located between the mechanism plates 106 and 107. Its object is to block the vents 106a, 107a located partly in the plate 106 and partly in the plate 107, as long as the shell is being accelerated. During this phase of movement, the acceleration reaction pressure is so great that the frictional forces caused thereby between the slide valve 110 and the plate 107 hold the slide valve firmly in its inward position, whereas on the acceleration ceasing the centrifugal force acting on the slide valve 110 brings it into its release position. The primer 14 is fixed in a holder 106b in the mechanism plate 106; it lies exposed in the recess 110 in the fuze screw and gas passages 11d extend upwardly from this recess to the chamber accommodating the fuze clockwork mechanism 12. A thin metal or plastic disc 111 covers the passages 11d.

This arrangement increases the safety of the fuze because, even if the percussion pin 13 should pierce the primer 14 during the acceleration phase of the fuzeparticularly while in the barrel of the gun--owing to a breakdown in the gear or an error in assembly, the force of the ignition jet from the primer can act in upward direction through the passages 11d, and the safety slide valve 110 cannot be overstressed to such an extent that would cause the detonator to be struck.

Jointly described, the arrangements improved by the present invention operate in the following manner:

After firing and as long as the shell is in the barrel and subjected to axial and rotational acceleration, all functional parts are generally first in their position of rest, including the detonator safety slide valve 110 (Fig. 5), until, on leaving the barrel, the acceleration ceases to act. The detonator safety slide valve 110 will then fly outwards to theperiphery of the mechanism plate 105 and exposethe vents 106a, 107a. An element, not described in detail but which locks the regulator 20, will move into its release position and free the clockwork mechanism, so that its gear train starts running. This will also liberate the rack 104 so that it can move in the direction of the arrow (Fig. 2) and the centrifugal force acting on the weight 102 will advantageously assist the driving centrifugal weight of the fuze clockwork mechanism during the initial phase. The supporting surface 102a provided on the centrifugal weight 102 prevents at first the intermediate lever 100 from moving, so that this lever, through the intermediary of a pin 38, prevents the safety latch 39, the arm of which bears against the rear side of the pin 38, from carrying outv any movement whatsoever, so that the percussion pin 13 remains-locked in safety position. Only when, ac-

cording to-the predetermined safety period, the rack 104' ing in counterclockwise direction. The latch 39 is thereby also immediately released and, in swinging about its bearing pin 28 in counterclockwise direction, liberates the collar 13b of the percussion pin. The safety period is then terminated and the shellcan now be caused to explode by direct impact, or if this has not taken place within a predetermined time, by self-destruction.

A further development of the detonator safety device is illustrated in Figs. 6 and 7. Whereas in the form of construction shown in Fig. 5, the detonator safety slide valve 110 is time-controlled, i.e. remains in its safety position merely under the action of the reaction pressure and friction during the acceleration phase of the shell and moves out of this position as soon as the shell has left the barrel, the development of the detonator safety device hereinafter described ensures safety up to about 50 to 200 metres from the barrel. To attain this, the safety slide valve 210 between the primer and the detonator (not shown) and fitted at 15 is constructed as a rotary slide valve and provided with a shaped hole 210a with the aid of which it is slipped on to the pin 211a of the latch arbor 211. The latch arbor is mounted in the mechanism plates 212 and 213 of the fuze clockwork mechanism and has on its upper end a collar 211b which is cut away on one side to form the locking surface 211a.

A shoulder 1000 is additionally provided on the back of the centrifugal lever 100 in such a manner that it prevents the latch arbor from turning in counterclockwise direction (Fig.7) under the action of the centrifugal force acting on the arm 21% of the rotary slide valve 210 during the rotation of the shell, as long as the point 10012 of the centrifugal lever 100 is under the influence of the centrifugal weight 102.

When after a predetermined time safety path (Fig. 4) has been travelled, the centrifugal weight 102 has reached its outward position with the rack 104 and the centrifugal lever 100 has turned about its axle 101 in counterclockwise direction, the locking of the latch arbor 211 by the shoulder 110 of the centrifugal lever is released and the rotary slide valve 210 can now swing out counterclockwise under the action of the centrifugal force, thereby turning its latch arbor 11.

The percussion pin 13 and the vents 106a are therefore freed simultaneously.

We claim:

1. Shell fuze with direct time-controlled impact and clockwork-controlled self-destruction device, comprising a percussion pin safety latch, a percussion pin having a gear thereon, a centrifugal two-armed lever having an abutment connected to indirectly contact said latch to control the release of said latch, a toothed rack element contacting one arm of said lever in safety position and during a predetermined safety period and in operative connection with a fuze movement, said element supporting the centrifugal lever during the safety period and meshing with the pinion of the gear mounted on the percussion pin and having a supporting surface of a length corresponding to the predetermined safety period at the end of which surface the centrifugal lever is released by being out of contact with the rack element.

2. Shell fuze according to claim 1, in which the toothed I rack on one end has a centrifugal weight secured thereto (Figs. 3 and 4) comes out of mesh with the pinion 23,

can movement take place suddenly, the point 10% of the lever dropping off precipitately from the edge 102a of the supporting surface 102a and the lever 100 swingto assist the movement drive in its initial start.

3. Shell fuze according to claim 1, in which the body of the fuze has an aperture therein to determine the position of the element supporting the centrifugal lever.

4. Shell fuze according to claim 1, in which a fuze base is provided with a firing hole for the percussion pin and which has a primer and a detonator therein in axial alignment with the pin, and in which a safety slide valve is provided arranged between plates within the base so that in the safety position of the valve the latter covers the'firing hole.

(Other references on following page) References Cited in the file of this patent UNITED STATES PATENTS Junghans Nov. 12, 1935 Junghans Jan. 13, 1925 5 Junghans Apr. 10, 1928 Varaud Aug. 27, 1929 

